1. Field of the Invention
This invention relates to a fertilizer absorption accelerator and a fertilizer composition and more particularly to a fertilizer absorption accelerator composition which is added to a fertilizer adapted for use on plants by application to or spray on roots, stems, leaves, or fruits thereof for the purpose of preventing the plants from developing physiological lesions due to nutrient deficiency.
2. Description of Related Art
It is known that plants require various nutrient elements for their growth and that they suffer obstruction of growth when they are not supplied sufficiently with nutrient elements. As respects the three major elements of fertilizer, for example, nitrogen forms a component element of proteins, phosphorus not only constitutes itself a component element of nucleic acids and phospholipids but also fulfills an important role in the energy metabolism and the reactions for synthesis and decomposition of substances, and potassium discharges physiological functions of mass metabolism and mass transfer. Insufficient supply of these main components generally renders the growth of plants inferior. Calcium is an important component for the constitution of plants themselves and cells thereof and plays the important role of balancing the metabolic system. It is, however, prone to assume the symptom of deficiency and induce such phenomena as, for example, tip rot in tomatoes, core rot in white rapes and cabbages, bitter pit in apples, and tip burn in strawberries.
Since these elements are not always present copiously in the soil, various kinds of fertilizer are used in the soil to ensure sufficient supply of nutrient elements. When the soil is deficient in nitrogen, phosphorus, and potassium, for example, the practice of incorporating a chemical fertilizer into the soil is followed.
As respects the physiological obstacle due to deficiency in calcium, the practice of precluding the calcium deficiency by incorporating lime or other calcium source into the soil has been often tried. More often than not, however, the calcium thus supplied is not thoroughly absorbed into the plants because part of the calcium reacts with the carbon dioxide in the air and escapes ultimately in the form of calcium carbonate into the underground, because the calcium reacts with other incorporated chemical fertilizer and consequently incurs inactivation, and because the incorporation of the chemical fertilizer and that of the calcium component are not well balanced. Even when the calcium is absorbed somehow or other through the root of a plant, it often fails to reach the site at which the physiological lesion actually develops because this element incurs unusual difficulty in migrating inside the system of a plant. When it reaches the site at all, it takes a considerable amount of time to do so and it fails to manifest an immediate effect on the lesion.
In recent years, therefore, it is tried to avoid a plant from a physiological lesion due to deficiency in calcium by directly spraying a calcium fertilizer in the form of an aqueous solution to leaves and fruits of the plant, which will easily suffer from such a lesion (the so-called foliage spray).
As compounds which are intended for use in such calcium fertilizers as utilize the technique of foliage spray mentioned above, such water-soluble calcium salts as calcium formate (JP-A-59-137,384), calcium acetate (JP-A-60-260,487), and calcium propionate (Japanese Patent Application No. 04-202,080) have been known. The calcium fertilizer including a calcium salt of high solubility and a calcium salt of low solubility in combination has been also known in JP-A 7-10666.
The direct spray of the aqueous solution of a calcium salt, however, has the problem of poor efficiency of absorption because the degree with which calcium is absorbed into the plant through the leaves and the fruits thereof is generally low. Further, an effort to spray such excessive fertilizer components as N, P, K, and calcium with a view to heightening the ratio of absorption ironically results in imparting stress to the plant and causes toxicity to the plant. The desirability of developing a measure for enabling a plant to attain efficient absorption of calcium and various other fertilizer components, therefore, has been finding widespread acceptance.